Search results for: Alessandra Ricca

Items from 1 to 20 out of 44 results

article

Perspective on innovative therapies for globoid cell leukodystrophy

Alessandra Ricca, Angela Gritti

Journal of Neuroscience Research > 94 > 11 > 1304 - 1317

Globoid cell leukodystrophy (GLD), or Krabbe's disease, is a lysosomal storage disorder resulting from deficiency of the lysosomal hydrolase galactosylceramidase. The infantile forms are characterized by a unique relentless and aggressive progression with a wide range of neurological symptoms and complications. Here we review and discuss the basic concepts and the novel mechanisms identified as key...

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Infrared vibrational and electronic transitions in the dibenzopolyacene family

Andrew L. Mattioda, Charles W. Bauschlicher, Jonathan D. Bregman, Douglas M. Hudgins, more

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy > 2014 > 130 > Complete > 639-652

We report experimental spectra in the mid-infrared (IR) and near-IR for a series of dibenzoacenes isolated in Ar matrices. The experiments are supported by Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations with both vibrational and electronic transitions studied. For the neutrals, we find good agreement between the experimental and B3LYP and BP86 results for all species...

article

Loss of a C₂H_n fragment from pyrene and circumcoronene

Charles W. Bauschlicher, Alessandra Ricca

Theoretical Chemistry Accounts > 2014 > 133 > 5 > 1-5

Reactions at the edge of pyrene and circumcoronene are studied using the B3LYP approach in conjunction with the 4-31G and 6-31G** basis sets. The loss of a C₂H_n fragment from the edge of either molecule requires more than 7 eV, which is much larger than for the loss of an H atom. Some paths can be broken down into a series of less energetic steps, but this does not change the overall endothermicity...

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The infrared spectra of C₉₆H₂₅ compared with that of C₉₆H₂₄

Charles W. Bauschlicher, Alessandra Ricca

Theoretical Chemistry Accounts > 2014 > 133 > 4 > 1-8

The addition of one H atom to C₉₆H₂₄ has been studied for the neutral, cation, and anion. Hydrogen atom binding at the solo site is the most favorable for all three charge states. The solo and duo sites are significantly more strongly bound than the endo positions. One extra hydrogen atom has very little effect on the infrared spectra. It is unlikely that species with one extra hydrogen could be identified...

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On the calculation of the vibrational frequencies of C6H4

Charles W. Bauschlicher, Alessandra Ricca

Chemical Physics Letters > 2013 > 566 > Complete > 1-3

DFT and CCSD(T) frequencies are compared with experiment for ortho-benzyne (C ₆ H ₄ ). Four bands are found to be in disagreement with experiment at the DFT level. Surprisingly the CCSD(T) method only brings the triple bond stretch into agreement with experiment, but leaves a sizable difference with experiment for the other three bands. The results for three isotopologues suggests...

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Naphthalene dimer and naphthalene dimer with Ar: calibration calculations and the effect of Ar on the stability and vibrational frequencies

Charles W. Bauschlicher, Alessandra Ricca

Theoretical Chemistry Accounts > 2013 > 132 > 11 > 1-8

The harmonic vibrational frequencies of naphthalene and its dimers are computed using density functional theory including an empirical correction for dispersion. The C–H out-of-plane bending modes in the naphthalene dimers show a red or a blue shift depending on the relative orientation of the two naphthalene molecules. The addition of Ar atoms does not significantly affect the vibrational frequencies,...

article

Plasma Membrane-Associated Glycohydrolases Along Differentiation of Murine Neural Stem Cells

Massimo Aureli, Angela Gritti, Rosaria Bassi, Nicoletta Loberto, more

Neurochemical Research > 2012 > 37 > 6 > 1344-1354

The activities of plasma membrane associated sialidase Neu3, total β-glucosidase, CBE-sensitive β-glucosidase, non-lysosomal β-glucosyl ceramidase GBA2, β-galactosidase, β-hexosaminidase and sphingomyelinase were determined at three different stages of differentiation of murine neural stem cell cultures, corresponding to precursors, commited progenitors, and differentiated cells. Cell immunostaining...

article

Formation of Complex Organics from Acetylene Catalyzed by Ionized Benzene

Paul O. Momoh, Abdel-Rahman Soliman, Michael Meot-Ner, Alessandra Ricca, more

Journal of the American Chemical Society > 2008 > 130 > 39 > 12848 - 12849

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The gas-phase catalytic formation of H2 by cations

Alessandra Ricca, Charles W. Bauschlicher

Chemical Physics Letters > 2008 > 463 > 4-6 > 327-329

We study the catalytic formation of H ₂ by CH3+ using high levels of theory. The first step involves the addition of an H atom to form CH4+. The second H addition reaction yields CH5+, which has the form CH3+–H2. Both of these reactions are exothermic and have no reaction barriers. The final step is the loss of H ₂ , which has no barrier in excess of the reaction energy. Because the...

article

The physisorption of CH4 on graphite and on a (9,0) carbon nanotube

Alessandra Ricca, Charles W. Bauschlicher

Chemical Physics > 2006 > 324 > 2-3 > 455-458

Our best estimates for the binding energy of methane on graphite, on a (9,0) single-walled carbon nanotube (SWCNT) and at the groove site between two (9,0) SWCNTs are 3.5±1, 2.9±1, and 5.6±1kcal/mol, respectively. Our computed values are in good agreement with the available experimental values. The calculations, therefore, support the current view that methane initially fills the groove site and then...

article

The adsorption of NO2 on (9,0) and (10,0) carbon nanotubes

Alessandra Ricca, Charles W. Bauschlicher

Chemical Physics > 2006 > 323 > 2-3 > 511-518

On the basis of calculations, the physisorption of NO ₂ , N ₂ O ₄ , and NO ₃ are estimated to be 5±2, 12±3, and 9±3kcal/mol, respectively. The chemisorption energy of two NO ₂ molecules on (9,0) and (10,0) tubes is computed to be 16 and 8kcal/mol, respectively, while the chemisorption of two NO ₃ molecules is much more exothermic. The implication of...

article

Effect of Packing and Tilt on the Rotational Barriers of an Amino, Nitro-Substituted Phenylene Ethynylene Trimer

Alessandra Ricca, Charles W. Bauschlicher

The Journal of Physical Chemistry B > 2005 > 109 > 18 > 9059 - 9065

article

Metal–nanotube interactions – binding energies and wetting properties

Amitesh Maiti, Alessandra Ricca

Chemical Physics Letters > 2004 > 395 > 1-3 > 7-11

Recent experiments indicate wide variation of the quality of metal–nanotube contacts with the choice of metal. With Au, Pt and Pd as examples, we present DFT results for the interaction of a metal atom, monolayer, multilayer and cluster with a graphene surface, a representative of wide-diameter carbon nanotubes. We also study nanotubes placed on flat metal surfaces. We discover interesting effects...

article

Current–voltage curves for molecular junctions: pyrene vs diphenylacetylene

Charles W. Bauschlicher, Alessandra Ricca, Yongqiang Xue, Mark A. Ratner

Chemical Physics Letters > 2004 > 390 > 1-3 > 246-249

The I–V curves are computed for 2,7-dithiolpyrene and 4,4 ^′ -dithiol-diphenylacetylene between two Au(111) surfaces. For a given bias, up to about 2.5 eV, the current for 2,7-dithiolpyrene is about half that for 4,4 ^′ -dithiol-diphenylacetylene. However, the fused benzene rings in 2,7-dithiolpyrene eliminate the loss of current associated with rotation about the central C ₂ ...

article

Current-voltage curves for molecular junctions: the effect of Cl substituents and basis set composition

Charles W. Bauschlicher, John W. Lawson, Alessandra Ricca, Yongqiang Xue, more

Chemical Physics Letters > 2004 > 388 > 4-6 > 427-429

Current-voltage characteristics of gold-benzene-1,4-dithiol-gold junctions are calculated using a combined density functional theory/non-equilibrium Green's functions approach with local atomic basis sets. Improving the basis set with the addition of polarization or diffuse functions has some effect on the computed I-V curves, but even the small valence double zeta sets yield reasonable results. The...

article

CO ₂ adsorption in single-walled carbon nanotubes

Martin Cinke, Jing Li, Charles W. Bauschlicher, Alessandra Ricca, more

Chemical Physics Letters > 2003 > 376 > 5-6 > 761-766

Adsorption of CO ₂ on purified single-walled carbon nanotubes (SWNTs) has been studied in the temperature range of 0-200 ^o C and found to be mainly a physisorption process. The SWNTs adsorb nearly twice the volume of CO ₂ compared to activated carbon. The experimental results yield a CO ₂ heat of adsorption of 2303 J/mol (0.024 eV) in SWNTs. Our computational study...

article

Do individual molecule rotational barriers explain the retention times of molecular memories?

Charles W. Bauschlicher, Alessandra Ricca

Chemical Physics Letters > 2003 > 375 > 5-6 > 459-462

We compute the rotational barriers for two molecules for which experimental memory retention times exist. The computed barriers for the neutral molecules and the cations do not explain the observed experimental results, but the anion barriers are consistent with the observations. The implications of this are discussed.

article

On the current flow for benzene-1,4-dithiol between two Au contacts

Charles W Bauschlicher, Alessandra Ricca, Natalio Mingo, John Lawson

Chemical Physics Letters > 2003 > 372 > 5-6 > 723-727

The current flow for a benzene-1,4-dithiol molecule between two Au contacts is computed. For most configurations considered, the computed current is an order of magnitude larger than experiment, as found by other groups. When the benzene-1,4-dithiol is bonded to the top of an fcc cluster of Au atoms, the current flow is significantly reduced, bringing it into better agreement with experiment. This...

article

Interaction of a conjugated phenylene ethynylene trimer with a Au(111) surface

Alessandra Ricca, Charles W. Bauschlicher

Chemical Physics Letters > 2003 > 372 > 5-6 > 873-877

The interaction of 4-[4′-(phenylethynyl)-phenylethynyl]-benzenethiols (PPBSH) with Au(111) surfaces has been studied using density functional theory and a cluster model. For PPBSH perpendicular to the surface, the threefold hollow is the most favorable site, but the energy difference between this and the least favorable site is only about 9 kcal/mol. The most stable form of PPBSH on the surface is...

article

Conductivity at low temperatures, are the rings eclipsed or perpendicular?

Charles W. Bauschlicher, Alessandra Ricca

Chemical Physics Letters > 2003 > 369 > 3-4 > 415-418

For seven and nine tolane molecules, forming a T-shaped arrangement, the conformation with eclipsed rings on each tolane molecule is more stable than the one with rings perpendicular to each other on each tolane molecule. The implication for the low temperature conductivity measurements is discussed.

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Search results for: Alessandra Ricca

Perspective on innovative therapies for globoid cell leukodystrophy

Infrared vibrational and electronic transitions in the dibenzopolyacene family

Loss of a C₂H_n fragment from pyrene and circumcoronene

The infrared spectra of C₉₆H₂₅ compared with that of C₉₆H₂₄

On the calculation of the vibrational frequencies of C6H4

Naphthalene dimer and naphthalene dimer with Ar: calibration calculations and the effect of Ar on the stability and vibrational frequencies

Plasma Membrane-Associated Glycohydrolases Along Differentiation of Murine Neural Stem Cells

Formation of Complex Organics from Acetylene Catalyzed by Ionized Benzene

The gas-phase catalytic formation of H2 by cations

The physisorption of CH4 on graphite and on a (9,0) carbon nanotube

The adsorption of NO2 on (9,0) and (10,0) carbon nanotubes

Effect of Packing and Tilt on the Rotational Barriers of an Amino, Nitro-Substituted Phenylene Ethynylene Trimer

Metal–nanotube interactions – binding energies and wetting properties

Current–voltage curves for molecular junctions: pyrene vs diphenylacetylene

Current-voltage curves for molecular junctions: the effect of Cl substituents and basis set composition

CO ₂ adsorption in single-walled carbon nanotubes

Do individual molecule rotational barriers explain the retention times of molecular memories?

On the current flow for benzene-1,4-dithiol between two Au contacts

Interaction of a conjugated phenylene ethynylene trimer with a Au(111) surface

Conductivity at low temperatures, are the rings eclipsed or perpendicular?

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